The invention concerns an installation for the treatment of a thread or the like with a treatment fluid such as liquid wax, oil or the like, during the winding process of the thread on a cross-wound bobbin or the like with a constant spool spindle rotational speed, with a treatment roller driven at a constant rotational speed one part of its peripheral area dipping into a bath containing the treatment fluid, said treatment roller having on its peripheral surface axially running grooves, said installation having two thread guides the first of which is stationary while the second can be moved essentially parallel to the axle of the treatment roller and which is constructed in such a manner that the threads which are stretched between them lie against the peripheral area of the treatment roller and this over a certain length.
In known installations of this type, the threads are pulled essentially vertically with regard to the axis of the treatment roller. Since on the one hand the treatment roller turns on itself, and on the other hand dips into the bath with the treatment fluid, its peripheral area is constantly wet with the treatment fluid so that the threads can pick up the latter. Since the cross-wound bobbin or the like, on which the threads are wound, has a growing diameter, even though the number of the rotations of the spindle remains constant, the speed of the thread continually increases, which results in the fact that the wetting of the thread with the treatment liquid becomes insufficient and this because of the fact that the treatment roller, whose peripheral speed is lower than the speed of the thread, always picks up an identical quantity of treatment fluid. Therefore, when the speed of the thread increases, the thread is led more and more at an angle over the treatment roller in order to increase the contact length between the thread and the peripheral area. Through this lengthening of the line of contact one attempts to reduce the loss of wetting which occurs when the thread speed increases so that the treatment of the thread with the treatment fluid occurs in a uniform manner and so that the quantity of treatment fluid per length of thread remains the same.
Nevertheless, the experience has been that with a smooth peripheral surface of a treatment roller it is especially unsatisfactory when the covering of the thread with a treatment fluid has to be especially intensive, as for example for seam thread. It has been noted that the thread at the beginning of the winding always picks up substantially more treatment fluid than at the end of the winding process even though the contact length or surface between the thread and the treatment roller is constantly increased. An unlimited increase of the contact surface is not possible because, on the one hand the spatial relationship of the winding machine is limited, and on the other hand because in an excessive increase of the contact surface the tension of the thread can be increased to the point where it would lead to the snapping of the thread. On the other hand a special intensive absorption, especially for a seam thread, of the treatment fluid is a requirement since the number of stitches in modern sewing machines (stitch per unit of time) has constantly increased and is still increasing.
Regardless of the above mentioned considerations against a further increase of the contact surface, the prior art has already thought of designing the treatment roller in a conical form in which the thread at increasing thread speed can be shifted to the areas of the larger diameter of the cone. Regardless of the increased thread tension it became clear that by this no substantial improvement could be obtained since the treatment fluid indicated a tendency to flow toward the tip, i.e. the smaller diameter of the cone. As a result of this the coating thickness of the treatment fluid is at its strongest where it is not desired, namely in the area of the roller which the thread touches at the beginning of the winding process.
Further, the prior art has attempted to install, between to co-axial spaced-apart circular discs, studs along the length of the discs, which thus represent the circumference of the roller. These studs are put on in an angle and are also constructed in a conical form; nevertheless this did not result in an improvement since the treatment fluid dripped off from these studs. Furthermore, one also has build into a cylindrical treatment roller wedge-shaped grooves which begin on the front side of the treatment roller and which continually advance and end in a point at the other front side of the treatment roller, in which the thread in the neighborhood on one such area is shifted towards the other front side and this in accordance with the increasing diameter of the bobbin and the increasing speed of the thread. Nevertheless, the distribution of the treatment fluid remained unsatisfactory.